Autothermal Reforming

Autothermal reforming, or ATR, produces hydrogen rich syngas from methane by combining partial oxidation with steam reforming inside a single reaction chamber, reacting methane with oxygen, and with either carbon dioxide or steam, so that the exothermic partial oxidation reaction supplies the heat the endothermic steam reforming reaction needs. Because the two reactions balance each other, autothermal reforming can run at essentially zero net enthalpy, unlike conventional steam methane reforming, which needs a substantial 206 kilojoules per mole of external heat to proceed. The process runs hot, with syngas leaving the reactor at 950 to 1,100 degrees Celsius and pressures as high as 100 bar, and unlike steam reforming, which burns air to raise steam for heat, autothermal reforming uses purified oxygen, which lets operators tune the ratio of hydrogen to carbon monoxide in the syngas it produces, 1 to 1 when carbon dioxide is used, 2.5 to 1 when steam is used, for different downstream chemical uses.